The present invention is related to an improved extractor structure, and more particularly to an extractor in which the claws can be easily opened/closed without deflection so as to truly grasp a work piece.
FIGS. 6 and 7 show a conventional complex extractor including a thread rod 51, a connecting seat 52, a pressboard seat 53, a spring 54 and a nut 55. The connecting seat 52 has an upward extending thread column 521 at the center. The pressboard seat 53 is formed with a central through hole 531 for the thread column 521 of the connecting seat 52 to pass through. The spring 54 is fitted around one end of the thread column 521 distal from the connecting seat 52. The nut 55 is screwed on the thread column 521 above the spring 54. The thread column 521 is formed with a central thread hole 522 through which the thread rod 51 is screwed. Several rotary arms 523 extend from the circumference of the connecting seat 52. Several grasping legs 524 are pivotally connected with the rotary arms 523. Several pressboards 532 extend from the circumference of the pressboard seat 53 corresponding to the rotary arms 523 of the connecting seat 52. The pressboards 532 serve to press the pivoted ends of the grasping legs 524. By means of adjusting the nut 55, the pressboard seat 53 can be moved up and down to press the pivoted ends of the grasping legs 524 so as to open or close the grasping legs 524 for holding a work piece.
When the nut 55 is screwed downward to push the pressboard seat 53, the action force can be hardly evenly distributed over the respective pressboards 532. Therefore, the grasping legs 524 cannot be accurately opened for truly grasping the work piece. It often takes place that one of the grasping legs 524 fails to truly operate. The spring 54 is compressed between the nut 55 and the pressboard seat 53. It is hard to prevent the pressboards 532 from being biased. As a result, only some of the grasping legs 524 can truly operate to grasp the work piece. Therefore, it often takes place that the extractor is detached from the work piece to lead to injury of a worker.
FIG. 8 shows an improved link-type extractor for overcoming the above problem. Such extractor includes a thread rod 6, a driving unit 7 and a driven unit 8. The driving unit 7 is formed with a central through hole 71. The driven unit 8 has a thread column 81 upward extending from the center of the driven unit 8 corresponding to the through hole 71 of the driving unit 7. An adjustment nut 83 is screwed on upper section of the thread column 81. The thread column 81 is formed with a central thread hole 811 through which the thread rod 6 is screwed. Several corresponding support arms 72, 82 extend from the circumferences of the driving unit 7 and the driven unit 8. The length of the support arm 72 of the driving unit 7 is larger than the length of the support arm 82 of the driven unit 8. The support arm 72 of the driving unit 7 is pivotally connected with one end of a claw 73. The driven unit 8 is pivotally connected with one end of a driven arm 84. A middle section of the claw 73 is pivotally connected with the other end of the driven arm 84. By means of adjusting the adjustment nut 83, the driving unit 7 is moved up and down to control the operation of the respective driven arm 84. Accordingly, the driven unit 8 can be operated to open or close the claws 73 without possibility of detachment.
The driving unit 7 and driven unit 8 of the link-type extractor are pivotally connected via the driven arms 84 and the claws 73. This solves the problem of uneven application force of the conventional complex extractor. However, when screwing the adjustment nut 83 to control the claws 73 to open or close, the driving unit 7 and the driven unit 8 are rotated via the thread column 81 and the nut 83. This increases the friction during rotation. Moreover, such extractor lacks any rectifying measure so that the claws 73 still cannot be truly moved in the same line. Therefore, the claws 73 tend to deflect. Accordingly, the above extractor still needs to be improved.